Tools
Subnet Calculator
Compute IPv4/IPv6 networks, split into subnets (VLSM) and check if an IP is in range. Everything runs in your browser.
Enter an IPv4 or IPv6 CIDR.
About this tool
The Subnet Calculator resolves, for IPv4 and IPv6, the network address, broadcast, host range and count, netmask and wildcard from a CIDR. It also splits into subnets (VLSM) and checks whether an IP is within a range.
- Convert between CIDR notation (/24) and netmask (255.255.255.0) instantly.
- Plan addressing by splitting a block into subnets of different sizes.
- Check whether a specific IP belongs to a given network.
Frequently asked questions
What does the /24 CIDR notation mean?
The number after the slash is the network bits. A /24 reserves 24 bits for the network and leaves 8 for hosts, that is 256 addresses (254 usable). The higher the number, the smaller the subnet.
What is VLSM?
Variable Length Subnet Masking means splitting a block into subnets of different sizes based on what each segment needs, using the address space more efficiently than cutting it all equally.